The goal of this research is the characterization of human myeloid leukemia cells using murine and human monoclonal antibody techniques to provide reagents that will be useful in the diagnosis and treatment of human myeloid leukemia. Monoclonal antibodies will be produced against cell surface antigens on normal and malignant myeloid cells with emphasis on myeloid precursor cells and their differentiation products. This technology also includes recently developed procedures to expand normal antibody producing B-lymphocyte cultures in large quantities by demethylation of cytosin in certain nucleotide sequences. The antigenic determinants for such antibodies will be biochemically characterized. The investigator will also include studies on the modulation potential of such antigens.